From: Antti Palosaari Date: Wed, 26 Feb 2014 23:30:35 +0000 (-0300) Subject: [media] DocBook: media: add some general info about RF tuners X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=8dfe644bf6c696b0f24d57f87fe25aea6cecb96a;p=openwrt%2Fstaging%2Fblogic.git [media] DocBook: media: add some general info about RF tuners Add some info what is RF tuner in context of V4L RF tuner class. Cc: Hans Verkuil Signed-off-by: Antti Palosaari Signed-off-by: Mauro Carvalho Chehab --- diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index 282f0a50433a..8c62ead889e4 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -5013,8 +5013,27 @@ defines possible values for de-emphasis. Here they are:
RF Tuner Control Reference - The RF Tuner (RF_TUNER) class includes controls for common features -of devices having RF tuner. + +The RF Tuner (RF_TUNER) class includes controls for common features of devices +having RF tuner. + + +In this context, RF tuner is radio receiver circuit between antenna and +demodulator. It receives radio frequency (RF) from the antenna and converts that +received signal to lower intermediate frequency (IF) or baseband frequency (BB). +Tuners that could do baseband output are often called Zero-IF tuners. Older +tuners were typically simple PLL tuners inside a metal box, whilst newer ones +are highly integrated chips without a metal box "silicon tuners". These controls +are mostly applicable for new feature rich silicon tuners, just because older +tuners does not have much adjustable features. + + +For more information about RF tuners see +Tuner (radio) +and +RF front end +from Wikipedia. + RF_TUNER Control IDs